U.S. patent number 10,444,198 [Application Number 15/484,324] was granted by the patent office on 2019-10-15 for piping inspection apparatus.
This patent grant is currently assigned to Hitachi, Ltd.. The grantee listed for this patent is Hitachi, Ltd.. Invention is credited to Toshimi Kimura, Naoyuki Kono, Masahiro Miki, Yuki Oshima.
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United States Patent |
10,444,198 |
Miki , et al. |
October 15, 2019 |
Piping inspection apparatus
Abstract
An ultrasonic transmission probe is arranged such that an
ultrasonic wave transmitted from the ultrasonic transmission probe
toward a pipe propagates in a thick part of the pipe, is at least
reflected on the outer peripheral face of the pipe, and travels
toward an inspection site on the pipe, and an ultrasonic reception
probe is arranged to be symmetrical to the ultrasonic transmission
probe with reference to the xz plane including the inspection site
and perpendicular to the center axis of the pipe.
Inventors: |
Miki; Masahiro (Tokyo,
JP), Oshima; Yuki (Tokyo, JP), Kono;
Naoyuki (Tokyo, JP), Kimura; Toshimi (Tokyo,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hitachi, Ltd. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Hitachi, Ltd. (Tokyo,
JP)
|
Family
ID: |
58547399 |
Appl.
No.: |
15/484,324 |
Filed: |
April 11, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170328869 A1 |
Nov 16, 2017 |
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Foreign Application Priority Data
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May 12, 2016 [JP] |
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2016-095912 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N
29/04 (20130101); G01N 29/223 (20130101); G01N
29/221 (20130101); G01N 2291/2634 (20130101) |
Current International
Class: |
G01N
29/22 (20060101); G01N 29/04 (20060101) |
Field of
Search: |
;73/628 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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27 51 810 |
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May 1979 |
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DE |
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2 031 385 |
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Mar 2009 |
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EP |
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2014-081376 |
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May 2014 |
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JP |
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Other References
Extended European Search Report in corresponding European
Application No. 17166434.5 dated Oct. 16, 2017. cited by
applicant.
|
Primary Examiner: Saint Surin; Jacques M
Attorney, Agent or Firm: Mattingly & Malur, PC
Claims
What is claimed is:
1. A piping inspection apparatus comprising: an ultrasonic
transmission probe arranged on a pipe and directed for transmitting
an ultrasonic wave toward the pipe; an ultrasonic reception probe
arranged on the pipe and configured to receive an ultrasonic wave;
and a piping inspection unit for inspecting the presence of damage
on the pipe on the basis of a reception result of the ultrasonic
reception probe, wherein the ultrasonic transmission probe is
arranged such that an ultrasonic wave transmitted from the
ultrasonic transmission probe toward the pipe propagates in a thick
part of the pipe, is reflected on the outer peripheral face of the
pipe once, and travels toward an inspection site on the pipe, and
the ultrasonic reception probe is arranged to be symmetrical to the
ultrasonic transmission probe with reference to a plane including
the inspection site and perpendicular to the center axis of the
pipe.
2. A piping inspection apparatus comprising: an ultrasonic
transmission probe arranged on a pipe and directed for transmitting
an ultrasonic wave toward the pipe; an ultrasonic reception probe
arranged on the pipe and configured to receive an ultrasonic wave;
and a piping inspection unit for inspecting the presence of damage
on the pipe on the basis of a reception result of the ultrasonic
reception probe, wherein the ultrasonic transmission probe is
arranged such that an ultrasonic wave transmitted from the
ultrasonic transmission probe toward the pipe propagates in a thick
part of the pipe, and is reflected on the outer peripheral face of
the pipe once, and travels toward an inspection site on the pipe,
and the ultrasonic reception probe is arranged to be symmetrical to
the ultrasonic transmission probe with reference to a plane
including the inspection site and the center axis of the pipe.
3. The piping inspection apparatus according to claim 1,
comprising: a transmission wedge present between the ultrasonic
transmission probe and the pipe; a reception wedge present between
the ultrasonic reception probe and the pipe; and a holding unit for
holding a distance between the transmission wedge and the reception
wedge.
4. The piping inspection apparatus according to claim 3, wherein
the holding unit can is configured to adjust the distance.
5. The piping inspection apparatus according to claim 3, wherein
the transmission wedge is arranged at an angle between 90.degree.
and 135.degree. on the pipe in the circumferential direction with
reference to a plane including the inspection site and the center
axis of the pipe.
6. The piping inspection apparatus according to claim 1, wherein
the piping inspection unit is configured to specify a
circumferential position of the damage on the pipe on the basis of
a ratio of a time after the ultrasonic transmission probe transmits
an ultrasonic wave until the ultrasonic reception probe receives
the ultrasonic wave while the ultrasonic transmission probe and the
ultrasonic reception probe are arranged on one side in a plane
including the inspection site and the center axis of the pipe to a
time after the ultrasonic transmission probe transmits an
ultrasonic wave until the ultrasonic reception probe receives the
ultrasonic wave while the ultrasonic transmission probe and the
ultrasonic reception probe are arranged on the other side in the
plane including the inspection site and the center axis of the
pipe.
7. The piping inspection apparatus according to claim 1, wherein
the ultrasonic transmission probe and the ultrasonic reception
probe are an ultrasonic array probe.
8. A piping inspection apparatus comprising: an ultrasonic
transmission probe arranged on a pipe and directed for transmitting
an ultrasonic wave toward the pipe; a first ultrasonic reception
probe arranged on the pipe and configured to receive an ultrasonic
wave; a second ultrasonic reception probe arranged on the pipe and
configured to receive an ultrasonic wave; and a piping inspection
unit for inspecting the presence of damage on the pipe on the basis
of a reception result of the first ultrasonic reception probe and a
reception result of the second ultrasonic reception probe, wherein
the ultrasonic transmission probe is arranged such that an
ultrasonic wave transmitted from the ultrasonic transmission probe
toward the pipe propagates in a thick part of the pipe, and is
reflected on the outer peripheral face of the pipe once, and
travels toward an inspection site on the pipe, the first ultrasonic
reception probe is arranged to be symmetrical to the ultrasonic
transmission probe with reference to a plane including the
inspection site and perpendicular to the center axis of the pipe,
and the second ultrasonic reception probe is arranged to be
symmetrical to the ultrasonic transmission probe with reference to
a plane including the inspection site and the center axis of the
pipe.
9. The piping inspection apparatus according to claim 8,
comprising: a transmission wedge present between the ultrasonic
transmission probe and the pipe; a first reception wedge present
between the first ultrasonic reception probe and the pipe; a second
reception wedge present between the second ultrasonic reception
probe and the pipe; a first holding unit for holding a distance
between the transmission wedge and the first reception wedge; and a
second holding unit for holding a distance between the transmission
wedge and the second reception wedge.
10. The piping inspection apparatus according to claim 9, wherein
the first holding unit is configured to adjust the distance between
the transmission wedge and the first reception wedge, and the
second holding unit is configured to adjust the distance between
the transmission wedge and the second reception wedge.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piping inspection apparatus for
inspecting the presence of damage on a pipe.
2. Description of the Related Art
Radiographic testing or ultrasonic testing is performed for damages
of pipes (such as cracks on inner peripheral faces of pipes)
provided in power plant or chemical plant. The radiographic testing
out of the two testing methods needs the works of installing a
radiation source and shielding a site to be inspected from the
surrounding, and has a restriction that person's entry is limited
during the inspection. It is therefore desirable that the
ultrasonic testing is performed for the presence of damage on a
pipe. For the ultrasonic testing, for example, JP 2014-81376 A
describes that an ultrasonic wave is transmitted or received by one
probe thereby to inspect the presence of damage on a pipe on the
basis of a reflection wave of the ultrasonic wave.
CITATION LIST
Patent Literature
Patent Literature 1: JP 2014-81376 A
SUMMARY OF THE INVENTION
A plurality of pipes are welded in order to provide relatively
longer pipes in power plant or chemical plant in many cases. In
such a case, a part where pipes are welded is protruded radially
outside from the outer peripheral face of the pipes ("weld
reinforcement" is present). For example, with the technique
described in JP 2014-81376 A, if a probe is arranged on the weld
reinforcement, the probe is unstable, and the presence of damage on
the pipe cannot be accurately inspected.
It is therefore an object of the present invention to provide a
piping inspection apparatus for accurately inspecting the presence
of damage on a pipe.
In order to achieve the object, in a piping inspection apparatus
according to the present invention, an ultrasonic transmission
probe is arranged such that an ultrasonic wave transmitted from the
ultrasonic transmission probe toward a pipe propagates in a thick
part of the pipe, is at least reflected on the outer peripheral
face of the pipe, and travels toward an inspection site on the
pipe, and an ultrasonic reception probe is arranged to be
symmetrical to the ultrasonic transmission probe with reference to
a plane including the inspection site and perpendicular to the
center axis of the pipe.
Further, in a piping inspection apparatus according to the present
invention, an ultrasonic transmission probe is arranged such that
an ultrasonic wave transmitted from the ultrasonic transmission
probe toward a pipe propagates in a thick part of the pipe, is at
least reflected on the outer peripheral face of the pipe, and
travels toward an inspection site of the pipe, and an ultrasonic
reception probe is arranged to be symmetrical to the ultrasonic
transmission probe with reference to a plane including the
inspection site and the center axis of the pipe.
According to the present invention, it is possible to provide a
piping inspection apparatus for accurately inspecting the presence
of damage on a pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an explanatory diagram of a piping inspection apparatus
according to a first embodiment of the present invention;
FIG. 2 is a configuration diagram of the piping inspection
apparatus according to the first embodiment of the present
invention;
FIG. 3 is a cross-section view along the line II-II in FIG. 1 of
the piping inspection apparatus according to the first embodiment
of the present invention;
FIG. 4 is an explanatory diagram of a pipe, an ultrasonic
transmission probe, an ultrasonic reception probe, and the like in
the piping inspection apparatus according to the first embodiment
of the present invention viewed in the negative x-axis
direction;
FIG. 5 is a flowchart of the processing performed by a flaw
detector control device provided in the piping inspection apparatus
according to the first embodiment of the present invention;
FIG. 6 is a transverse cross-section view including an ultrasonic
transmission probe and an ultrasonic reception probe in a piping
inspection apparatus according to a second embodiment of the
present invention;
FIG. 7 is an explanatory diagram of a pipe, the ultrasonic
transmission probe, the ultrasonic reception probe, and the like in
the piping inspection apparatus according to the second embodiment
of the present invention viewed in the negative x-axis
direction;
FIG. 8 is a transverse cross-section view of an ultrasonic
transmission probe and an ultrasonic reception probe arranged on
one side in the yz plane in a piping inspection apparatus according
to a third embodiment of the present invention;
FIG. 9 is a transverse cross-section view of the ultrasonic
transmission probe and the ultrasonic reception probe arranged on
the other side in the yz plane in the piping inspection apparatus
according to the third embodiment of the present invention;
FIG. 10 is a transverse cross-section view including an ultrasonic
transmission probe and an ultrasonic reception probe in a piping
inspection apparatus according to a fourth embodiment of the
present invention;
FIG. 11 is an explanatory diagram of a pipe, the ultrasonic
transmission probe, the ultrasonic reception probe, and the like in
the piping inspection apparatus according to the fourth embodiment
of the present invention viewed in the negative x-axis
direction;
FIG. 12 is a flowchart of the processing performed by the flaw
detector control device provided in the piping inspection apparatus
according to the fourth embodiment of the present invention;
FIG. 13 is a longitudinal cross-section view of an ultrasonic
transmission probe provided in a piping inspection apparatus
according to a variant of the present invention; and
FIG. 14 is a transverse cross-section view illustrating a route of
an ultrasonic wave transmitted from an ultrasonic transmission
probe in a piping inspection apparatus according to another variant
of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
<Configuration of Piping Inspection Apparatus>
FIG. 1 is an explanatory diagram of a piping inspection apparatus
100 according to a first embodiment.
A water-wall W will be briefly described prior to the description
of the piping inspection apparatus 100.
The water-wall W is directed for partitioning the inside and the
outside of a boiler furnace (not illustrated) provided in a thermal
plant (not illustrated). The water-wall W includes a plurality of
pipes G through which cool water circulates, and a plurality of
film plates P which are provided between the adjacent pipes G, G
and are welded on the pipes G, G.
A cylindrical pipe G includes base pipes Ga, Gb, and a
circumferential welded part Gc where the base pipes Ga and Gb are
welded. The circumferential welded part Gc is protruded radially
outside from the outer peripheral face of the base pipes Ga and Gb,
where damage such as crack occurs in more cases than on the base
pipes Ga and Gb. The first embodiment will be described assuming
that an inspection is carried out as to whether an "axial crack"
(damage) substantially parallel to the center axis of the pipe G is
present on the inner peripheral face of the circumferential welded
part Gc. Further, a cylindrical part where a material of the pipe G
is present (or the pipe G itself) is also called "thick part Gi"
(see FIG. 3).
The piping inspection apparatus 100 is directed for inspecting the
presence of damage on the pipe G. As illustrated in FIG. 1, the
piping inspection apparatus 100 includes an ultrasonic transmission
probe 11, a wedge 12 (transmission wedge), an ultrasonic reception
probe 21, a wedge 22 (reception wedge), a holding unit 41, an
ultrasonic flaw detector 50, and a flaw detector control device 60
(piping inspection unit).
The ultrasonic transmission probe 11 is directed for transmitting
an ultrasonic wave toward the pipe G, and is arranged on the pipe G
via the wedge 12.
FIG. 2 is a configuration diagram of the piping inspection
apparatus 100. The wedges 12 and 22 (see FIG. 1) are not
illustrated in FIG. 2.
The ultrasonic transmission probe 11 illustrated in FIG. 2 is an
ultrasonic array probe including a plurality of oscillators 11a and
an acoustic adjustment layer 11b. The oscillators 11a are
piezoelectric devices arranged in line, and are connected to a
transmission flaw detection circuit 51 via wirings m. A pulse
voltage is applied from the transmission flaw detection circuit 51
to the oscillators 11a via the wirings m so that the respective
oscillators 11a oscillate.
The acoustic adjustment layer 11b is a resin layer for efficiently
putting an ultrasonic wave generated by oscillation of the
oscillators 11a into the pipe G (see FIG. 1), and is arranged
outside the oscillators 11a (closer to the pipe G).
The configuration of the ultrasonic transmission probe 11 is not
limited to one illustrated in FIG. 2. For example, an acoustic lens
(not illustrated) for converging an ultrasonic wave may be provided
outside the acoustic adjustment layer 11b. Further, a backing
member (not illustrated) for suppressing extra oscillation of the
oscillators 11a may be provided inside the oscillators 11a.
The ultrasonic reception probe 21 is configured to be capable of
receiving an ultrasonic wave transmitted from the ultrasonic
transmission probe 11, and is arranged on the pipe G via the wedge
22 (see FIG. 1). The ultrasonic reception probe 21 is an ultrasonic
array probe including a plurality of oscillators 21a and an
acoustic adjustment layer 21b. The configuration of the ultrasonic
reception probe 21 is similar to that of the ultrasonic
transmission probe 11, and thus the description thereof will be
omitted.
As illustrated in FIG. 2, an ultrasonic wave (oscillation) from a
reflection source is converted into an electric signal (reflection
signal) in each oscillator 21a, and the electric signal is output
to a reception flaw detection circuit 52 via wirings n. The
reflection source is an axial crack on the inner peripheral face of
the pipe G (see FIG. 1), for example.
The ultrasonic flaw detector 50 includes, though not illustrated,
electric circuits such as CPU (Central Processing Unit), ROM (Read
Only Memory), RAM (Random Access Memory), and various interfaces.
The ultrasonic flaw detector 50 reads the programs stored in the
ROM and develops them into the RAM so that the CPU performs various
processing. As illustrated in FIG. 2, the ultrasonic flaw detector
50 includes the transmission flaw detection circuit 51 and the
reception flaw detection circuit 52.
The transmission flaw detection circuit 51 is connected at its
input side to a transmission control circuit 61 via a wiring r, and
is connected at its output side to each oscillator 11a via the
wirings m. The transmission flaw detection circuit 51 applies a
pulse voltage at a predetermined timing to each oscillator 11a of
the ultrasonic transmission probe 11 on the basis of a control
signal from the transmission control circuit 61.
The reception flaw detection circuit 52 is connected at its input
side to each oscillator 21a of the ultrasonic reception probe 21
via the wirings n, and is connected at its output side to a
reception control circuit 62 via a wiring s. The reception flaw
detection circuit 52 fetches an electric signal from each
oscillator 21a of the ultrasonic reception probe 21, and outputs
the electric signal as predetermined data to the reception control
circuit 62.
The flaw detector control device 60 includes, though not
illustrated, electric circuits such as CPU, ROM, RAM, and various
interfaces, and reads the programs stored in the ROM and develops
them into the RAM so that the CPU performs various processing. As
illustrated in FIG. 2, the flaw detector control device 60 includes
the transmission control circuit 61 connected to the transmission
flaw detection circuit 51, and the reception control circuit 62
connected to the reception flaw detection circuit 52.
The transmission control circuit 61 outputs a control signal for
oscillating each oscillator 11a at a predetermined timing to the
transmission flaw detection circuit 51. In the example illustrated
in FIG. 2, the transmission control circuit 61 oscillates each
oscillator 11a arranged in line, which is farther away from the
oscillator 11a around the center, at an earlier timing. Thereby, an
ultrasonic wave (spherical wave) occurring along with oscillation
of each oscillator 11a converges toward the focus. The oscillation
timing at each oscillator 11a is controlled such that the focus is
positioned at a predetermined inspection site Q (see FIG. 3) on the
pipe G. Thereby, the damage on the pipe G can be detected at high
sensitivity. The "inspection site Q" is a site where the presence
of damage is to be inspected on the pipe G.
The reception control circuit 62 illustrated in FIG. 2 has a
function of inspecting the present of damage on the pipe G on the
basis of a reception result of the ultrasonic reception probe 21.
The reception control circuit 62 has a function of outputting a
state of the inspection site Q on the pipe G as image data to a
display device (not illustrated).
FIG. 3 is a cross-section view along the line II-II in FIG. 1 of
the piping inspection apparatus 100 according to the first
embodiment. "Inside" illustrated in FIG. 3 indicates being closer
to the boiler furnace (not illustrated) than to the water-wall W
(see FIG. 1), and "outside" indicates to be farther away from the
boiler furnace.
As illustrated in FIG. 3, it is assumed that the center axis of the
pipe G is y-axis, a line perpendicular to the wall of the film
plate P and crossing with the y-axis is z-axis, and a line
perpendicular to the y-axis and the z-axis is x-axis. A bold arrow
illustrated in FIG. 3 indicates a route through which an ultrasonic
wave (high-directivity ultrasonic beam) propagates in the thick
part Gi of the pipe G.
Other pipe (not illustrated) is installed around the water-wall W
inside the water-wall W (in the depth side in FIG. 1) in many
cases, and ash is attached inside the water-wall W even when the
boiler furnace (not illustrated) is stopped. Thus, the pipe G
inside the water-wall W is difficult to inspect by an inspector.
Thus, according to the first embodiment, the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21 are
arranged outside the water-wall W (closer to the lower side in FIG.
1 or on the positive z-axis side in FIG. 3) to inspect the pipe
G.
The wedge 12 illustrated in FIG. 3 is a member present between the
ultrasonic transmission probe 11 and the pipe G, and is fixed on
the ultrasonic transmission probe 11 by metal part or screw. An
ultrasonic wave from each oscillator 11a (see FIG. 2) of the
ultrasonic transmission probe 11 is incident into the pipe G via
the wedge 12. The wedge 12 is made of epoxy resin or polystyrene
resin, and has a function of stabilizing an installation angle of
the ultrasonic transmission probe 11 and enhancing a transmission
efficiency of an ultrasonic wave. A face of the wedge 12 contacting
with the outer peripheral face of the pipe G is formed according to
a curvature of the outer peripheral face of the pipe G (or such
that a gap is not present between the wedge 12 and the pipe G).
FIG. 4 is an explanatory diagram of the pipe G, the ultrasonic
transmission probe 11, the ultrasonic reception probe 21, and the
like viewed in the negative x-axis direction. The film plate P (see
FIG. 3) is not illustrated in FIG. 4.
The wedge 22 illustrated in FIG. 4 is a member present between the
ultrasonic reception probe 21 and the pipe G, and is fixed on the
ultrasonic reception probe 21 by metal part or screw. An ultrasonic
wave is incident into each oscillator 21a (see FIG. 2) of the
ultrasonic reception probe 21 via the wedge 22.
The holding unit 41 is a member for holding a distance (=2 L)
between the wedge 12 and the wedge 22, and has a rod shape in the
example illustrated in FIG. 4. The holding unit 41 is fixed at one
end on the wedge 12 and is fixed at the other end on the wedge
22.
When the inspector inspects the presence of damage on the pipe G, a
contact medium such as water, oil, or glycerin paste is applied on
the faces of the wedges 12 and 22 on the pipe G. The inspector
performs the ultrasonic testing while supporting the holding unit
41 or the like by hand.
<Arrangement of Ultrasonic Transmission Probe and Ultrasonic
Reception Probe>
The description will be made below assuming that the inner
peripheral face (particularly a position on the z-axis in FIG. 3)
of the pipe G closer to (inside) the boiler furnace is an
"inspection site Q" and an inspection is carried out as to whether
an axial crack is present at the "inspection site Q." In the
example illustrated in FIGS. 3 and 4, an axial crack V1 is present
on the z-axis on the inner peripheral face of the pipe G.
As illustrated in FIG. 3, the ultrasonic transmission probe 11 is
arranged such that an ultrasonic wave transmitted from the
ultrasonic transmission probe 11 toward the pipe G propagates in
the thick part Gi of the pipe G, is reflected on the outer
peripheral face of the pipe G once, and travels toward the
inspection site Q on the pipe G.
An angle .alpha. illustrated in FIG. 3 indicates a position where
an ultrasonic wave is reflected on the outer peripheral face of the
pipe G in the circumferential direction with reference to the
z-axis (0.degree.). The angle .alpha. is set such that when an
axial crack V1 is present at the inspection site Q, an ultrasonic
wave reflected on the outer peripheral face of the pipe G is
incident into the axial crack V1 substantially perpendicularly in
planar view. In other words, the angle .alpha. is set assuming that
an axial crack V1 substantially parallel to a plane including the
center axis (the y-axis) of the pipe G (the yz plane in FIG. 3) is
present on the inner peripheral face of the pipe G.
The angle .alpha. is preferably between 35.degree. and 55.degree..
This is because when the angle .alpha. is within the range, an
ultrasonic wave is incident into the axial crack V1 substantially
perpendicularly in planar view. Thereby, the reflection intensity
of the ultrasonic wave at the axial crack V1 can be further
enhanced than when an ultrasonic wave is incident into the axial
crack V1 in other direction.
An angle .beta. illustrated in FIG. 3 indicates an installation
position of the wedge 12, 22 in the circumferential direction with
reference to the z-axis (0.degree.). The angle .beta. of k is set
such that an ultrasonic wave is reflected at the angle .alpha. on
the other peripheral face of the pipe G. It is preferable that the
wedges 12, 22 are arranged at an angle between 90.degree. and
135.degree. and more preferably between 105.degree. and 135.degree.
on the pipe G in the circumferential direction with reference to
the yz plane including the inspection site Q and the center axis
(the y-axis) of the pipe G. This is because an ultrasonic wave
reflected on the outer peripheral face of the pipe G is incident
into the axial crack V1 substantially perpendicularly in planar
view and an ultrasonic wave reflected on the axial crack V1 travels
toward the ultrasonic reception probe 21 via the wedge 22.
A refraction angle .theta. illustrated in FIG. 3 is a refraction
angle of an ultrasonic wave on the interface between the wedge 12
and the pipe G. The refraction angle .theta. is preferably between
35.degree. and 45.degree.. This is because an ultrasonic wave
reflected on the outer peripheral face of the pipe G is incident
into the axial crack V1 substantially perpendicularly in planar
view.
An angle .gamma. illustrated in FIG. 4 is formed between a plane
perpendicular to the center axis (the y-axis) of the pipe G and a
route of an ultrasonic wave transmitted from the ultrasonic
transmission probe 11. The angle .gamma. is set as needed in
consideration of the inner diameter and outer diameter of the pipe
G, a thickness of the circumferential welded part Gc, an
interference of an ultrasonic wave on the film plate P (see FIG.
3), and the like. The angle .gamma. is preferably between
20.degree. and 70.degree.. This is because an ultrasonic wave
reflected on the outer peripheral face of the pipe G travels toward
the inspection site Q in side view. The wedges 12 and 22 are
configured such that the angles .theta., .alpha., .beta., and
.gamma. are kept while the wedges 12 and 22 are pressed onto the
pipe G.
As illustrated in FIG. 4, the ultrasonic transmission probe 11 and
the ultrasonic reception probe 21 are arranged on one side and the
other side of the circumferential welded part Gc including the
inspection site Q in the axial direction (in the y-axis direction)
of the pipe G, respectively. More specifically, the ultrasonic
reception probe 21 is arranged to be symmetrical to the ultrasonic
transmission probe 11 with reference to the xz plane including the
inspection site Q and perpendicular to the center axis (the y-axis)
of the pipe G.
Thus, the angles .theta., .alpha., .beta., and .gamma. have
substantially the same values on the transmission side and the
reception side of an ultrasonic wave. Consequently, a route of an
ultrasonic wave from the ultrasonic transmission probe 11 toward
the axial crack V1 and a route of an ultrasonic wave reflected on
the axial crack V1 and traveling toward the ultrasonic reception
probe 21 appear to be overlapped in planar view (see FIG. 3). That
is, the ultrasonic reception probe 21 is arranged to be symmetrical
to the ultrasonic transmission probe 11 with reference to the xz
plane, and thus the routes are symmetrical to each other with
reference to the xz plane (see FIG. 4).
It is preferable that the holding unit 41 illustrated in FIG. 4 can
adjust a distance between the wedge 12 and the wedge 22 (=2 L). For
example, the holding unit 41 may include two mutually-engaged rails
(not illustrated) and screws (not illustrated) for holding the
full-length of the rails. With the configuration, the wedge 12 is
fixed on one rail and the wedge 22 is fixed on the other rail. The
holding unit 41 can adjust the length in this way, thereby
performing the ultrasonic testing on another pipe (not illustrated)
with different inner diameter in the configuration illustrated in
FIGS. 3 and 4.
<Processing by Flaw Detector Control Device>
FIG. 5 is a flowchart of the processing performed by the flaw
detector control device 60.
It is assumed that the ultrasonic transmission probe 11 and the
ultrasonic reception probe 21 are arranged as illustrated in FIGS.
3 and 4 on "START" time of FIG. 5. When the inspector presses the
start button (not illustrated) of the flaw detector control device
60 (see FIG. 2), a series of processing illustrated in FIG. 5 are
started.
In step S101, the flaw detector control device 60 transmits an
ultrasonic wave from the ultrasonic transmission probe 11 via the
transmission control circuit 61 (see FIG. 2). The ultrasonic wave
transmitted from the ultrasonic transmission probe 11 is refracted
on the interface between the ultrasonic transmission probe 11 and
the wedge 12, is then reflected on the outer peripheral face of the
pipe G, and travels toward the inspection site Q as described
above.
If an axial crack V1 is present at the inspection site Q, the
ultrasonic wave is reflected on the axial crack V1, is further
reflected on the outer peripheral face of the pipe G, and travels
toward the ultrasonic reception probe 21.
Further, if an axial crack V1 is not present at the inspection site
Q, the ultrasonic wave is repeatedly reflected on the outer
peripheral face or the inner peripheral face of the pipe G, and
attenuates. Consequently, the ultrasonic wave is not received by
the ultrasonic reception probe 21 or the slight ultrasonic wave due
to back bead welding inside the pipe is received.
In step S102, the flaw detector control device 60 determines
whether a predetermined reflection signal is present. That is, in
step S102, the flaw detector control device 60 determines whether
the intensity of the reflection signal from the ultrasonic flaw
detector 50 (see FIG. 2) is a predetermined threshold or more. The
"predetermined threshold" is a determination reference as to
whether an axial crack V1 is present on the inner peripheral face
of the pipe G, and is previously set. In step S102, when the
predetermined reflection signal is present (S102: Yes), the
processing of the flaw detector control device 60 proceeds to step
S103.
In step S103, the flaw detector control device 60 determines that
the pipe G is damaged. That is, the flaw detector control device 60
determines that the axial crack V1 (damage) is present on the inner
peripheral face of the pipe G. In this case, the circumferential
welded part Gc is repaired or the pipe G is replaced.
On the other hand, in step S102, when the predetermined reflection
signal is not present (S102: No), the processing of the flaw
detector control device 60 proceeds to step S104.
In step S104, the flaw detector control device 60 determines that
the pipe G is not damaged. That is, the flaw detector control
device 60 determines that the axial crack V1 (damage) is not
present on the inner peripheral face of the pipe G.
After performing the processing in step S103 or S104, the flaw
detector control device 60 terminates the processing (END). The
determination result of the flaw detector control device 60 or the
images acquired in the ultrasonic testing are displayed on the
display device (not illustrated) such as display.
A circumferential position of the axial crack V1 is not previously
specified, and thus the inspector circumferentially scans the
ultrasonic transmission probe 11 and the ultrasonic reception probe
21 on the pipe G thereby to confirm the presence of a reflection
signal. As described above, the wedges 12 and 22 are configured
such that the angles .alpha., .beta., .gamma., and .theta. are
kept, and the distance between the wedges 12 and 22 is held by the
holding unit 41. Thus, the inspector circumferentially scans the
pipe G while pressing the wedges 12 and 22 onto the pipe G, thereby
inspecting the presence of damage with high accuracy at each part
of the pipe G in the circumferential direction.
Additionally, for an axial crack on the inner peripheral face of
the pipe G outside the boiler furnace (not illustrated), the
ultrasonic transmission probe 11 and the ultrasonic reception probe
21 are arranged outside the boiler furnace and the wedges (not
illustrated) may be configured such that an ultrasonic wave travels
toward the inspection site (is not reflected on the outer
peripheral face of the pipe G), for example.
<Effects>
According to the first embodiment, the ultrasonic transmission
probe 11 and the ultrasonic reception probe 21 are arranged on one
side and the other side of the circumferential welded part Gc in
the axial direction, respectively. Thereby, the presence of an
axial crack V1 at the circumferential welded part Gc can be
inspected without pressing the wedges 12 and 22 onto the
circumferential welded part Gc. If a wedge is pressed onto
non-uniform weld reinforcement of the circumferential welded part
Gc, a gap is caused between the wedge and the circumferential
welded part Gc, and thus an ultrasonic wave attenuates in the gap.
For example, with the conventional technique described in JP
2014-81376 A, when a probe is arranged on weld reinforcement of the
circumferential welded part Gc, the probe is unstable and an
ultrasonic wave is likely to attenuate due to a gap between the
wedge and the probe. To the contrary, according to the first
embodiment, the ultrasonic testing is performed while the wedges 12
and 22 are tightly attached on the pipe G via a contact medium such
as glycerin, thereby restricting attenuation of an ultrasonic
wave.
The ultrasonic testing can be performed farther away from (outside)
the boiler furnace even when an obstacle such as the water-wall W
(see FIG. 1) is present and the ultrasonic testing is difficult to
perform closer to (inside) the boiler furnace. Thereby, it is
possible to appropriately and easily inspect whether damage is
present on the inner peripheral face of the pipe G closer to the
boiler furnace.
The ultrasonic transmission probe 11 is arranged at the angles
.alpha., .beta., .gamma., and .theta., and thus an ultrasonic wave
is incident into the axial crack V1 substantially perpendicularly
in planar view (see FIG. 3). Thereby, the reflection intensity of
the ultrasonic wave at the axial crack V1 takes a relatively high
value, thereby detecting the axial crack V1 at high
sensitivity.
The ultrasonic reception probe 21 is arranged to be symmetrical to
the ultrasonic transmission probe 11 with reference to the xz
plane. Thereby, the ultrasonic wave reflected on the axial crack V1
can be received by the ultrasonic reception probe 21 at high
sensitivity.
Further, according to the first embodiment, the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21 employ
an ultrasonic array probe. Thereby, a timing to oscillate the
oscillators 11a can be electronically controlled, an ultrasonic
wave can be converged at any position, and an ultrasonic wave can
propagate in any direction. Further, the sector scanning method for
scanning an ultrasonic wave in a fan-like shape is employed so that
a position of a focus of an ultrasonic wave can be adjusted in
consideration of an error in deformation even when the
circumferential welded part Gc is deformed to be flattened or the
like. Thereby, the axial crack V1 on the pipe G can be detected
with high accuracy.
Second Embodiment
A second embodiment is different from the first embodiment in that
the ultrasonic transmission probe 11 and an ultrasonic reception
probe 31 are arranged to be symmetrical to each other with
reference to the yz plane in order to inspect the presence of a
circumferential crack (which will be called "circumferential crack
V2" below: see FIG. 6) on the inner peripheral face of the pipe G.
Other points are similar to the first embodiment. Thus, only the
difference from the first embodiment will be described and the
repeated description will be omitted.
FIG. 6 is a transverse cross-section view including the ultrasonic
transmission probe 11 and the ultrasonic reception probe 31 in a
piping inspection apparatus 100A according to the second
embodiment.
The piping inspection apparatus 100A illustrated in FIG. 6 includes
the ultrasonic transmission probe 11, the ultrasonic reception
probe 31, wedges 12, 32, a holding unit 42, the ultrasonic flaw
detector 50, and the flaw detector control device 60. The
configurations of the ultrasonic flaw detector 50 and the flaw
detector control device 60 are similar to those in the first
embodiment (see FIG. 2).
The ultrasonic transmission probe 11 is arranged such that an
ultrasonic wave transmitted from the ultrasonic transmission probe
11 toward the pipe G propagates in the thick part Gi of the pipe G,
is reflected on the outer peripheral face of the pipe G once, and
travels toward the inspection site Q on the pipe G. An installation
angle (or the angles .theta., .alpha., .beta., and .gamma.) of the
ultrasonic transmission probe 11 relative to the inspection site Q
is similar to the installation angle of the ultrasonic transmission
probe 11 described in the first embodiment (see FIGS. 3 and 4).
Thus, a route through which an ultrasonic wave from the ultrasonic
transmission probe 11 toward the inspection site Q propagates is
also similar to that in the first embodiment (see FIGS. 3 and
4).
The ultrasonic reception probe 31 is arranged to be symmetrical to
the ultrasonic transmission probe 11 with reference to the yz plane
including the inspection site Q and the center axis (the y-axis) of
the pipe G. The angles .alpha., .beta., .theta., and .gamma. (see
FIG. 7) indicating an installation angle of the ultrasonic
reception probe 31 are substantially the same as the angles
.alpha., .beta., .theta., and .gamma. (see FIG. 7) indicating the
installation angle of the ultrasonic transmission probe 11.
The holding unit 42 is a member for holding a distance between the
wedge 12 and the wedge 32, and has an arc shape in planar view in
the example illustrated in FIG. 6. It is preferable that the
holding unit 42 can adjust the distance between the wedge 12 and
the wedge 32. This is because the ultrasonic testing can be
performed on another pipe (not illustrated) with different inner
diameter in the configuration illustrated in FIGS. 6 and 7.
FIG. 7 is an explanatory diagram of the pipe G, the ultrasonic
transmission probe 11, the ultrasonic reception probe 31, and the
like viewed in the negative x-axis direction.
As illustrated in FIG. 7, a route of an ultrasonic wave from the
ultrasonic transmission probe 11 toward the circumferential crack
V2 and a route of an ultrasonic wave reflected on the
circumferential crack V2 and traveling toward the ultrasonic
reception probe 31 appear to be overlapped in side view. That is,
the routes are symmetrical to each other with reference to the yz
plane. A distance between the ultrasonic transmission probe 11 and
the xz plane (which is also a distance between the ultrasonic
reception probe 31 and the xz plane) is set as needed on the basis
of the inner diameter, the outer diameter, and the like of the pipe
G.
The processing performed by the flaw detector control device 60 are
similar to those in the first embodiment (see FIG. 5), and thus the
description thereof will be omitted.
<Effects>
According to the second embodiment, the ultrasonic transmission
probe 11 and the ultrasonic reception probe 31 are arranged on one
side (upward) of the circumferential welded part Gc in the axial
direction. Thereby, the presence of a circumferential crack V2 on
the circumferential welded part Gc can be detected without pressing
the wedges 12 and 32 onto the circumferential welded part Gc.
Further, the ultrasonic transmission probe 11 is arranged at the
angles .alpha., .beta., .gamma., and .theta. so that an ultrasonic
wave is incident into the circumferential crack V2 substantially
perpendicularly in side view (see FIG. 7). Thereby, the reflection
intensity of the ultrasonic wave at the circumferential crack V2 is
relatively high, and thus the circumferential crack V2 can be
detected at high sensitivity.
Third Embodiment
A third embodiment is different from the first embodiment in that a
circumferential position of an axial crack V3 (see FIG. 8) is
specified on the basis of a time from transmission to reception of
an ultrasonic wave. The arrangement of the ultrasonic transmission
probe 11 and the ultrasonic reception probe 21 is similar to that
in the first embodiment (see FIGS. 3 and 4). Thus, only the
difference from the first embodiment will be described, and the
repeated description will be omitted.
FIG. 8 is a transverse cross-section view of the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21 on one
side in the yz plane in a piping inspection apparatus 100B
according to the third embodiment.
The ultrasonic reception probe 21 is not illustrated in FIG. 8, but
the ultrasonic reception probe 21 is positioned immediately below
the ultrasonic transmission probe 11. In the example illustrated in
FIG. 8, an axial crack V3 is present at an angle .epsilon. in the
circumferential direction with reference to the z-axis.
As illustrated in FIG. 8, the flaw detector control device 60
inspects the presence of an axial crack V3 while the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21 (not
illustrated) are arranged on one side (on the right side in the
Figure) in the yz plane including the inspection site Q and the
center axis (the y-axis) of the pipe G. The flaw detector control
device 60 measures a time t1 after the ultrasonic transmission
probe 11 transmits an ultrasonic wave until the ultrasonic
reception probe 21 receives the ultrasonic wave.
FIG. 9 is a transverse cross-section view of the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21
arranged on the other side in the yz plane.
As illustrated in FIG. 9, the flaw detector control device 60
inspects the presence of an axial crack V3 while the ultrasonic
transmission probe 11 and the ultrasonic reception probe 21 (not
illustrated) are arranged on the other side (on the left side in
the Figure) in the yz plane including the inspection site Q and the
center axis (the y-axis) of the pipe G. The flaw detector control
device 60 measures a time t2 after the ultrasonic transmission
probe 11 transmits an ultrasonic wave until the ultrasonic
reception probe 21 receives the ultrasonic wave.
In the example illustrated in FIG. 9, the position of the axial
crack V3 is closer to one side (the right side in the Figure) in
the yz plane, and thus the time t2 is longer than the time t1. As a
ratio of the time t2 to the time t1 is larger, the circumferential
angle .epsilon. is larger. The flaw detector control device 60
specifies the circumferential position (or the angle .epsilon.) of
the damage on the pipe G on the basis of the ratio between the time
t1 and the time t2.
<Effects>
According to the third embodiment, a circumferential position (the
angle .epsilon.) of the axial crack V3 can be specified on the
basis of the ratio between the time t1 and the time t2. A position
of the axial crack V3 is specified in this way, thereby accurately
specifying the defect position and preventing erroneous
determination.
Fourth Embodiment
A fourth embodiment is configured such that the ultrasonic
reception probe 31 (see FIG. 10) arranged to be symmetrical to the
ultrasonic transmission probe 11 with reference to the yz plane is
added to the configuration of the first embodiment thereby to
inspect both axial crack and circumferential crack on the pipe G.
Other points (such as arrangement of the ultrasonic transmission
probe 11 and the ultrasonic reception probe 21) are similar to the
first embodiment. Thus, only the difference from the first
embodiment will be described and the repeated description will be
omitted.
FIG. 10 is a transverse cross-section view including the ultrasonic
transmission probe 11 and the ultrasonic reception probe 31 in a
piping inspection apparatus 100C according to the fourth
embodiment.
FIG. 10 illustrates that a circumferential crack V2 is present at
the inspection site Q, but an axial crack may be present at the
inspection site Q in some cases.
The piping inspection apparatus 100C illustrated in FIG. 10
includes the ultrasonic transmission probe 11, the wedge 12
(transmission wedge), the ultrasonic reception probe 21 (first
ultrasonic reception probe: see FIG. 11), the wedge 22 (first
reception wedge: see FIG. 11), the ultrasonic reception probe 31
(second ultrasonic reception probe), and the wedge 32 (second
reception wedge). The piping inspection apparatus 100C further
includes the holding unit 41 (first holding unit), the holding unit
42 (second holding unit), the ultrasonic flaw detector 50, and the
flaw detector control device 60 in addition to the above
components. The configurations of the ultrasonic flaw detector 50
and the flaw detector control device 60 are similar to those in the
first embodiment (see FIG. 2).
The ultrasonic transmission probe 11 is arranged on the pipe G via
the wedge 12 such that an ultrasonic wave transmitted from the
ultrasonic transmission probe 11 toward the pipe G propagates in
the thick part Gi of the pipe G, is reflected on the outer
peripheral face of the pipe G once, and travels toward the
inspection site Q on the pipe G.
The wedge 12 is a member present between the ultrasonic
transmission probe 11 and the pipe G, and is fixed on the
ultrasonic transmission probe 11.
The ultrasonic reception probe 31 is directed for detecting a
circumferential crack on the inner peripheral face of the pipe G,
and is arranged on the pipe G via the wedge 32. As illustrated in
FIG. 10, the ultrasonic reception probe 31 is arranged to be
symmetrical to the ultrasonic transmission probe 11 with reference
to the yz plane including the inspection site Q and the center axis
(the y-axis) of the pipe G.
The wedge 32 is a member present between the ultrasonic reception
probe 31 and the pipe G, and is fixed on the ultrasonic reception
probe 31.
The holding unit 42 is a member for holding a distance between the
wedge 12 and the wedge 32, and has an arc shape in planar view. The
holding unit 42 is fixed at one end on the wedge 12 and is fixed at
the other end on the wedge 32.
FIG. 11 is an explanatory diagram of the pipe G, the ultrasonic
transmission probe 11, the ultrasonic reception probes 21, 31, and
the like viewed in the negative x-axis direction.
The ultrasonic reception probe 21 is directed for detecting an
axial crack on the inner peripheral face of the pipe G, and is
arranged on the pipe G via the wedge 22. As illustrated in FIG. 11,
the ultrasonic reception probe 21 is arranged to be symmetrical to
the ultrasonic transmission probe 11 with reference to the xz plane
including the inspection site Q and perpendicular to the center
axis (the y-axis) of the pipe G.
The wedge 22 is a member present between the ultrasonic reception
probe 21 and the pipe G, and is fixed on the ultrasonic reception
probe 21.
The holding unit 41 is a member for holding a distance between the
wedge 12 and the wedge 22, and has a rod shape in the example
illustrated in FIG. 11. The holding unit 41 is fixed at one end on
the wedge 12 and is fixed at the other end on the wedge 22.
It is preferable that the holding unit 41 can adjust a distance
between the wedge 12 and the wedge 22. Similarly, it is preferable
that the holding unit 42 illustrated in FIG. 10 can adjust a
distance between the wedge 12 and the wedge 32. This is because the
ultrasonic testing can be performed on another pipe (not
illustrated) with different inner diameter and outer diameter in
the configuration illustrated in FIGS. 10 and 11.
<Processing by Flaw Detector Control Device>
FIG. 12 is a flowchart of the processing performed by the flaw
detector control device 60.
In step S201, the flaw detector control device 60 transmits an
ultrasonic wave from the ultrasonic transmission probe 11.
In step S202, the flaw detector control device 60 determines
whether a predetermined reflection signal from the ultrasonic
reception probe 21 for detecting axial crack is present. When the
predetermined reflection signal from the ultrasonic reception probe
21 is present (S202: Yes), the processing of the flaw detector
control device 60 proceeds to step S203.
In step S203, the flaw detector control device 60 determines that
the pipe G is damaged. That is, the flaw detector control device 60
determines that an axial crack (damage) is present on the inner
peripheral face of the pipe G.
In step S202, when the predetermined reflection signal is not
present (S202: No), the processing of the flaw detector control
device 60 proceeds to step S204.
In step S204, the flaw detector control device 60 determines
whether a predetermined reflection signal from the ultrasonic
reception probe 31 for detecting circumferential crack is present.
When the predetermined reflection signal from the ultrasonic
reception probe 31 is present (S204: Yes), in step S203, the flaw
detector control device 60 determines that the pipe G is damaged.
That is, the flaw detector control device 60 determines that a
circumferential crack (damage) is present on the inner peripheral
face of the pipe G.
In step S204, when the predetermined reflection signal is not
present (S204: No), the processing of the flaw detector control
device 60 proceeds to step S205.
In step S205, the flaw detector control device 60 determines that
the pipe G is not damaged. That is, the flaw detector control
device 60 determines that neither axial crack (damage) nor
circumferential crack (damage) is present on the inner peripheral
face of the pipe G.
After performing the processing in step S203 or S205, the flaw
detector control device 60 terminates the series of processing
(END).
<Effects>
According to the fourth embodiment, the presence of an axial crack
can be inspected by use of the ultrasonic transmission probe 11 and
the ultrasonic reception probe 21, and the presence of a
circumferential crack can be inspected by use of the ultrasonic
transmission probe 11 and the ultrasonic reception probe 31. The
distance between the wedges 12 and 22 can be held by the holding
unit 41 and the distance between the wedges 12 and 32 can be held
by the holding unit 42. Thus, the inspector has only to move the
ultrasonic transmission probe 11 or the ultrasonic reception probes
21, 31 axially or circumferentially while bringing the holding
units 41 and 42 by hand, thereby alleviating the working loads on
the inspector.
<Variants>
The piping inspection apparatus 100 and the like according to the
present invention have been described above by way of the
embodiments, but the present invention is not limited thereto and
can be variously changed.
For example, the description has been made assuming that the
ultrasonic transmission probe 11 and the wedge 12 are separate
parts and the ultrasonic reception probe 21 and the wedge 22 are
separate parts according to the first embodiment (see FIG. 4), but
the present invention is not limited thereto as described
below.
FIG. 13 is a longitudinal cross-section view of an ultrasonic
transmission probe 11D provided in a piping inspection apparatus
according to a variant.
As illustrated in FIG. 13, the ultrasonic transmission probe 11D
may include a wedge part 11d. The wedge part 11d is installed at
the opening of a housing 11c housing the oscillators 11a and the
acoustic adjustment layer 11b therein. Though not illustrated, the
ultrasonic reception probe may similarly include a wedge part. The
configuration illustrated in FIG. 13 may be added with the backing
member or acoustic lens.
The description has been made assuming that an ultrasonic wave is
reflected on the outer peripheral face of the pipe G once until the
ultrasonic wave reaches the inspection site Q, but as described
below, the ultrasonic transmission probe 11 and the like may be
arranged such that an ultrasonic wave propagates in the thick part
Gi of the pipe G and is at least reflected on the outer peripheral
face of the pipe G (or is reflected on the inner peripheral face of
the pipe G once or more times, or is reflected on the outer
peripheral face of the pipe G once or more times).
FIG. 14 is a transverse cross-section view illustrating a route of
an ultrasonic wave transmitted from the ultrasonic transmission
probe 11 in a piping inspection apparatus 100E according to another
variant.
For example, according to the first embodiment, when the pipe G is
relatively thin, an ultrasonic wave may not be incident into the
inspection site Q at an appropriate angle though it is reflected on
the outer peripheral face of the pipe G once. In such a case, it is
preferable to set the circumferential angle .beta. indicating an
installation position of the wedge 12, 22 to be larger. That is, it
is preferable that an ultrasonic wave repeatedly reflected on the
thick part Gi of the pipe G is further reflected at the angle
.alpha.. Thereby, an ultrasonic wave is incident into the axial
crack V1 substantially perpendicularly in planar view, thereby
enhancing the reflection intensity of the ultrasonic wave at the
axial crack V1.
In the example illustrated in FIG. 14, an ultrasonic wave refracted
on the interface between the wedge 12 and the pipe G is
sequentially reflected on the inner peripheral face, the outer
peripheral face, the inner peripheral face, and the outer
peripheral face of the pipe G, and travels toward the inspection
site Q. A route of an ultrasonic wave reflected on the axial crack
V1 at the inspection site Q and traveling toward the ultrasonic
reception probe 21 is substantially the same as the route
illustrated in FIG. 14 in planar view. The aforementioned contents
can be applied to the second, third, and fourth embodiments.
The configuration in which the piping inspection apparatus 100
includes the holding unit 41 (see FIG. 4) has been described
according to the first embodiment, but the holding unit 41 may be
omitted and the inspector may perform the ultrasonic testing while
bringing the wedges 12, 22 by hand. This is similarly applicable to
the second, third, and fourth embodiments.
In the configuration of the first embodiment (see FIGS. 3 and 4),
the ultrasonic reception probe 21 may be moved to be symmetrical to
the ultrasonic transmission probe 11 with reference to the yz plane
(see FIG. 6) and inspect the presence of a circumferential crack
after inspecting the presence of an axial crack on the pipe G.
Thereby, not only the presence of an axial crack but also the
presence of a circumferential crack can be inspected. The
ultrasonic transmission probe 11 may be moved to be symmetrical to
the ultrasonic reception probe 21 with reference to the yz plane
instead of moving the ultrasonic reception probe 21.
In the configuration of the second embodiment (see FIGS. 6 and 7),
the ultrasonic reception probe 31 may be moved to be symmetrical to
the ultrasonic transmission probe 11 with reference to the xz plane
(see FIG. 4) and inspect the presence of an axial crack after
inspecting the presence of a circumferential crack V2 on the pipe
G. Thereby, not only the presence of a circumferential crack but
also the presence of an axial crack can be inspected. The
ultrasonic transmission probe 11 may be moved to be symmetrical to
the ultrasonic reception probe 31 with reference to the xz plane
instead of moving the ultrasonic reception probe 31.
The description has been made assuming that the piping inspection
apparatus 100C includes one ultrasonic transmission probe 11 and
two ultrasonic reception probes 21, 31 according to the fourth
embodiment (see FIGS. 10 and 11), but the present invention is not
limited thereto. For example, two ultrasonic transmission probes
and one ultrasonic reception probe may be provided. With such a
configuration, one ultrasonic transmission probe 11 is arranged to
be symmetrical to the ultrasonic reception probe 21 with reference
to the xz plane including the inspection site Q and perpendicular
to the center axis (the y-axis) of the pipe G. Further, the other
ultrasonic transmission probe (not illustrated) is arranged to be
symmetrical to the ultrasonic reception probe 21 with reference to
the yz plane including the inspection site Q and the center axis
(the y-axis) of the pipe G.
Another ultrasonic transmission probe (not illustrated) arranged to
be symmetrical to the ultrasonic reception probe 21 with reference
to the yz plane may be added to the configuration of the fourth
embodiment. That is, two ultrasonic transmission probes and two
ultrasonic reception probes may be provided. Thereby, the presence
of circumferential cracks at two points on the pipe G in the center
axis direction (in the y-axis direction) can be inspected, thereby
alleviating the working loads of the ultrasonic testing.
The description has been made assuming that the presence of damage
at the circumferential welded part Gc is inspected according to
each embodiment, but the base pipes Ga and Gb (see FIG. 1) can be
inspected in a similar manner.
The description has been made assuming that the presence of damage
on the pipe G is inspected in the water-wall W (see FIG. 1) for
partitioning the inside and the outside of the boiler furnace (not
illustrated) according to each embodiment, but the present
invention is not limited thereto. That is, each embodiment can be
applied to inspect various pipes provided in power plant or
chemical plant. Many pipes (not illustrated) are provided near the
walls in order to secure the installation space for devices (not
illustrated) in power plant or the like in many cases. In this way,
it is possible to appropriately inspect the presence of damage on a
pipe in the method according to each embodiment even when a gap
between the pipes and the wall is very small.
The description has been made assuming that the ultrasonic
transmission probe 11 or the ultrasonic reception probe 21 employs
an ultrasonic array probe according to each embodiment, but the
present invention is not limited thereto. For example, other kind
of probe such as single element type ultrasonic probe may be
employed.
Each embodiment may be combined as needed. For example, the third
embodiment and the fourth embodiment may be combined thereby to
inspect the presence of an axial crack or circumferential crack on
the pipe G and to specify a position of an axial crack (angle s:
see FIGS. 8 and 9).
Each embodiment has been described in detail in order to
understandably explain the present invention, and does not
necessarily need to include all the components described above.
Part of the configuration of each embodiment may be added with
other configuration, deleted, or replaced therewith. Further, the
aforementioned mechanisms or components, which are regarded
necessary for the description, have been illustrated, and all the
mechanisms and components for the products are not necessarily
illustrated.
REFERENCE SIGNS LIST
100, 100A, 100B, 100C, 100D, 100E piping inspection apparatus 11,
11D ultrasonic transmission probe 11d wedge part 12 wedge
(transmission wedge) 21 ultrasonic reception probe (first
ultrasonic reception probe) 22 wedge (reception wedge, first
reception wedge) 31 ultrasonic reception probe (second ultrasonic
reception probe) 32 wedge (second reception wedge) 41 holding unit
(first holding unit) 42 holding unit (second holding unit) 50
ultrasonic flaw detector 61 flaw detector control device (piping
inspection unit) G pipe Gi thick part Q inspection site
* * * * *